Divine Favor (DF) is considered an attribute, though it functions in a different way.
It's initial value is fixed at 99 for all characters, throughout the entire game (it cannot be manipulated during character creation).
It functions as a battery for prayers: praying will consume a certain amount, depending on the saint, and more DF can be spent to increase the chance of success.
Wicked acts may decrease DF also.
It is regained slowly as time passes in-game - the speed depending on the character's Religious Training - but can be regained more quickly through prayer, confession, donations to church or by attending mass.